- 
eres 
1873] — 
3, 
NATURE 
435 
the'stoppers or corks being at once inserted, the vessels and takes place and the fluids thus situated rapidly become turbid. 
their contents were set aside to cool. When the filtered infusion 
of hay or turnip had been rapidly cooled down to about 110° F. 
(by letting the beaker containing it stand in a large basin of cold 
water), it was inoculated with some of a turbid infusion of hay 
swarming with active Bacteria and Vibriones--in the proportion 
of one drop of the turbid fluid to each fluid ounce of the now 
clear filtered infusion*, The beaker was then placed upon a 
sand-bath, and its contained fluid (in which a thermometer was 
immersed) gradually raised to the required temperature. The 
fluid was maintained at the same temperature for five minutes by 
alternately raising the beaker from and replacing it upon the 
sand-bath. The bottles to be used were then one by one un- 
corked, emptied, and refilled to the brim with the heated, in- 
oculated fluid.t The corks or stoppers were at once very tightly 
pressed down so as to leave no air between them and the surface 
of the fluids. The beaker was then replaced upon the sand- 
bath and the gas turned on more fully, in order that the experi- 
mental fluid might be rapidly raised to a temperature 9° F. (5° 
C.) higher than it had been before. A/ter five minutes’ exposure 
to this temperature other bottles were filed in the same manner, 
and so on for the various temperatures the influence of which it 
was desired to test. . 
Thus prepared, the bottles and tubes have been exposed 
during the day to a temperature ranging from 65° to 75° F. 
And generally one had not to wait long in order to ascertain 
what the results were to be. In some cases, if the contents of 
the vessels were to become turbid, this was more or less mani- 
fest after an interval of forty-eight hours. In other cases, how- 
ever, the turbidity manifested itself three or more days later, 
and the reason of this difference will be fully discussed in a sub- 
sequent communication. 
For the sake of simplicity and brevity, the necessary particu- 
lars concerning the 102 experiments have been embodied in the 
table which will be found below. : 
The experimental results here tabulated seem naturally di- 
visible into three groups. Thus, when heated only to 131° 
F., all the infusions became turbid within two days, just as the 
inoculated saline solutions had done.t Heated to 158° F. all 
the inoculated organic infusions remained clear, as had been the 
case with the saline solutions in my previous experiments, when 
heated to 140° F. There remains, th-refore, an intermediate 
heat zone (ranging from a little below 140° to a little below 
158° F.), after an exposure to which the inoculated organic 
infusions are apt to become more slowly turbid, although in- 
oculated saline solutions raised to the same temperatures inva- 
riably remain unaltered. The full explanation of these 
apparent anomalies I propose to make the subject of a future 
communication to the Royal Society ; meanwhile we may quite 
safely conclude that Bacteria, Vibriones, and their supposed 
germs are either actually killed or else completely deprived of 
their powers of multiplication afier a brief exposure to the tem- 
perature of 158° F. (70° C.). 
This evidence now in our possession as to the limits of ‘ vital 
resistance” to heat displayed by Bacteria; Vibriones, and their 
supposed germs in neutral saline solutions, and in neutral or 
acid organic infusions, is most pertinent and valuable when con- 
sidered in relation to that supplied by other sets of experiments 
bearing upon the all-important problem of the Origin of Life. 
These latter experiments alone may possibly leave doubt in many 
minds ; but the more thoroughly they are considered in relation 
to the evidence brought forward in this communication, the more 
fully, I venture to think, will every lingering doubt as to the 
proper conclusion to be arrived at be dispelled. 
Thus, we now know that boiled turnip- or hay-infusions ex- 
posed to ordinary air, exposed to filtered air, to calcined air, or 
shut off altogether from contact with air, are more or less prone 
to swarm with Bacteria and Vibriones in the course of from two 
to six days. But, placed under sligh'ly different conditions such 
as were employed in the inoculation experiments above quoted, 
although infusions of the same nature do not undergo ‘*‘ sponta- 
neous” putrefaciive changes, yet w! enliving Bacteriaand Vibriones 
are added and not subsequently heated, putrefaction invariably 
tightly fitting corks ; and the latter I find have answered quite as well as 
the former Onthe whole I have ‘ound ‘ightly corked 1 oz. phials to be about 
the most convenient vessels to employ in these inoculation exprriments. 
* It was found desirable to filter the infusions a‘ter they h-d been boiled, 
because the boiling generally somewhat impaired their clearness. ‘ 
+ At this stage, of course, very great care is needed in order to avoid all 
chance of accidental contamination either with living organisms or with un- 
heated fragments or particles of orzanic matter. 
4 In the experiments already referred to, 
| 
There is therefore nothing in the conditions themselves tending 
to hinder the process of putrefaction, so long as living units are 
there to initiate it. Our experiments now show that as long as 
the added Bacteria, Vibriones, and there supposed germs are sub- 
| jected to a heat not exceeding 131° F. (55° C.), putrefaction in- 
variably occurs within two days, whilst, on the contrary, whenever 
they are subjected to a temperature of 158° F. (70° C.) putrefac- 
tion does not occur. To what can this difference be due, except 
to the fact that the previously living organisms which, when 
living, always excite putrefaction, have been killed by the tempe- 
rature of 158° F.? It would be of no avail to suppose that the 
absence of putrefaction in these latter cases is due to the fact that 
a heat of 158° F., instead of killing the organisms and their germs, 
merely annuls their powers of reproduction, because in the other 
series of experiments (with which these have to be compared) 
where similar fluids are exposed to ordinary or purified air, or 
are shut off from the influence of air altogether, the most active 
putrefaction and multiplication of organisms takes place in two, 
three, or four days, in spite of the much more potent heat of 
212° F., to which any pre-existing germs or organisms must have 
been subjected. The supposition, therefore, that the Bacteria, 
Vibriiones, and their germs were not killed in our inoculation 
experiments at the temperature of 158° F., but were merely de- 
prived of their powers of reproduction, would be no gain to 
those who desire to stave off the admission that Bacteria and 
Vibrones can be proved to arise de xovo in certain cases. Let us 
assume this—which is indisputably proved by these inoculation 
experiments—viz. that an exposure to a temperature of 158° F. 
(70° C.) for five minutes deprives Bacteria, Vibriones, and their 
germs of their usual powers of growth and reproduction—that is 
that it reduces them to a state of potential, if not necessarily to 
one of actual death. What end would be served by such a 
reservation? The impending conclusion would not be staved 
off by means of it. The explanation of what occurs in the other 
set of experiments, where the much more potent heat of 212° F. 
is employed, still would not be possible without having recourse 
to the supposition of a de ovo origination of living units, so 
long as those which may have pre-existed in the flask could be 
proved to have been reduced to such a state of potential death. 
It would be preposterous, and contrary to the whole order of 
nature, to assume that the vastly increased destructive influence 
of a heat of 212° F. had restored vital properties which a 
lesser amount (158° F.) of the same influence had completely 
annulled. 
The evidence supplied by these different series of experiments 
in whichever way it is regarded, as it seems to me, absolutely 
compels tbe logical reasoner to conclude that the swarms of 
living organisms which so often make their appearance in boiled 
infusions treated in one or other of the various modes already 
proved to be either destructive or exclusive of pre-existing living 
things, are the products of a new brood of ‘living particles, ” — 
which, in the absence of any co-ex.sting living organisms, must 
have taken origin in the fluid itself. For this mode of origin of 
living units, so long spoken of and repudiated as ‘‘ spontaneous 
generation,” I have proposed the new term Archebiosis. 
Inoculation Experiments made with the view of ascertaining the 
Temperatures at which Bacteria, Vibriones, and their Supposea 
Germs are killed in Organic Infusions. 
NeEuTRAL HAY INFUSION. 
Temp. to Selick Nukes of Ex-| Date of Turbidity, |Results at Expira- 
exposed. periments made. if any. tion of the 8th day. 
oO 
(ee) 24 hours Turbid, 
31°F 48 hours All turbid. 
5 in 48 hours 
in 60 hours 
140°F, 9 im 3 days All turbid. 
I in days 
\2in § days Three turbid. 
149° F 4 (rin 8 days One clear. 
158° F. 15 All clear. 
167° F 4 All clear. 
* 176LF 
- (80°C.) § 12 All clear. 
